Soil infiltration properties affected by typical plant communities on steep gully slopes on the Loess Plateau of China

Abstract

Soil infiltration plays an important role in the processes of soil moisture, runoff generation, erosion, and nutrient movement under different climatic zones. Vegetation restoration may greatly affect soil infiltration process via altering soil and vegetation properties in arid and semi-arid region. However, few studies have been carried out to evaluate soil infiltration properties on steep gully slopes covered by typical plant communities in this region. This study was conducted to quantify the effects of typical plant communities on soil infiltration properties, and identify the main influencing factors on steep gully slopes of the Loess Plateau, China. Six typical plant communities of two shrubs (Caragana korshinskii and Hippophae rhamnoide) and four grasses (Artemisia sacrorum, Artemisia giraldii, Bothriochloa ischaemum, and Carex lanceolata) were selected to measure soil infiltration rate by a disc infiltrometer under four pressure heads of 0, −3, −6, and −12 cm. The results showed that soil infiltration properties of initial infiltration rate (IIR), steady infiltration (SIR), and hydraulic conductivity (Ks) were significantly affected by plant communities. IIR, SIR, and Ks varied from 1.54 to 0.27 mm min−1, 0.94 to 0.09 mm min−1, and 0.80 to 0.07 mm min−1 with the means of 0.78, 0.42, and 0.33 mm min−1. Plant communities of Artemisia sacrorum had the maximum IIR, SIR, and Ks, whereas Carex lanceolata had the minimum ones. Overall, IIR, SIR, and Ks of shrub communities were 14.7%, 4.9%, and 3.0% higher than those of grass communities. IIR, SIR, and Ks of shrub and grass communities with tap root systems were 1.90, 2.36, and 2.28 times greater than those with fibrous root systems. Variations in soil infiltration properties under different plant communities can be explained by the changes in soil texture, organic matter content, plant litter density, and root mass density. And plant litter and root were the main factors attributing to the changes in soil infiltration properties between different plant communities. The results are helpful to understand the differences in soil water storage, runoff, and erosion between different plant communities on steep gully slopes in arid and semi-arid regions.